Sound amplifier



C. MCLEAN SOUND AMPLIFIER June 20, 1933.

Filed Feb. 19, 1930 gwuemtoz cum/r455 Mel/541V Patented June 20, 1933 UNITED STATES PATENT. @FFIQE SOUND AMPLIFIER Application filed February 19, 1930.

This invention appertains toradio broadcasting and receiving sets and more partlcularly to novel means for amplifying the sound waves without distortion thereof so as to materially increase the volume of said waves.

One of the primary objects of my invention is the provision of means for amplifying the sound waves by the provision of the use of a sealed air-tight container or bell having air under pressure therein with a microphone and a loud speaker at the respective ends thereof so that the sound waves are made to pass through the compressed air, it being found that the passage of the waves through the compressed air will materially amplify the same.

Another important object of my invention is the provision of an improved loud speaker embodying a sealed container or bell having air under pressure therein with a receiver or speaker connected with the radio receiving set placed in the sealed container or hell at one end thereof and a microphone or transmitter arranged at the opposite end of the container or bell for receiving the sound waves from the receiver or speaker, the transmitter or microphone being in turn connected with a loud speaker arranged exteriorly of the bell, whereby the amplified sound waves can be thrown into the atmosphere.

A further object of my invention is the provision of a novel collecting port arranged in the sealed container or hell for receiving the microphone, the collector or shield acting as means for guiding the sound waves transmitted to the compressed air in the sealed container or hell against the diaphragm of the microphone.

A still further object of my invention is to provide an improved amplifying device of the above character, which will be durable and etficient in use, one that will be simple and easy to manufacture and one which can .be placed upon the market at a reasonable cost.

With these and other objects in view, the invention consists in the novel construction, arrangement, and formation of parts, as will be hereinafter more specifically described,

Serial No. 429,723.

claimed, and illustrated in the accompanying drawing, in which drawing:

The figure is a diagrammatic showing of my improved loud speaker showing the same in longitudinal section.

Referring to the drawing in detail, the letter A generally indicates my improved loud speaker which comprises a sealed container or bell B preferably formed of metal of the desired gage and of sufiicient strength to hold the air under pressure therein, said air being forced in the bell B through a suitable air supply valve 5 from any source of supply. The bell should likewise be provided with an air pressure gage 6 of any standard construction.

As shown, the sealed container or bell B is of a substantially conical body 7 having an arcuate end wall 8.

The narrow or apex end of the body 7 is provided with a neck 9 while the arcuate end wall 8 in alignment with said neck 9 is provided with a neck 10.

The improved device A is adapted to be interposed between the usual radio receiving set (not shown) and any preferred type of loud speaker and in accordance with my invention I place a receiver or speaker 15 within the sealed container or hell B adjacent to the narrow or converged end therv of and the usual loud speaker wires 16 for the radio receiving set (not shown) is led through the neck 9 into the bell and connected with said receiver or speaker. A cement or other filler 16 can be placed in the neck 9 around the wires 16.

At the opposite end of the bell and interiorly of the same and in longiiudinal alignment with the receiver or speaker 15, I place a microphone 18, which is in turn connected with a loud speaker or receiver 19 arranged exteriorly of the bell by suitable connection 20 which extends through the neck 10. A suitable cement 21 is placed in the neck around the connection 20.

If desired, a collector shield can be placed around the microphone 10, the same being indicated by the reference character 22, so as to direct the waves against the diaphragm of the microphone.

By the use of compressed air in the container, I have found that the sound waves are amplified and thus the volume of the receiving set is greatly increased by the use of my device.

Ch nges in details may be made Without departing from the spirit or the scope of this invention, but

What I claim as new is:

1. In a device of the class described, a sealed container having air under pressure therein, a speaker arranged in said container at one end thereof, a. microphone in said container at the opposite end thereof, and an exteriorly arranged loud speaker mounted upon said container and operatively connected with the microphone.

2. In a device of the class described, a sealed container having air under pressure therein, including an elongated conical body and an arcuate end Wall connected with the large end of the conical body, a speaker arranged in the narrow end of the conical portion of the body facing toward the arouate end Wall, a microphone arranged in the container facing the speaker and adjacent to the arcuate end Wall, and a loud speaker mounted upon and arranged exteriorly of the container and operatively connected to the microphone.

In testimony whereof I aflix my signature.

CHARLES MCLEAN. 

